The present invention relates to a process for the simple production of .kappa.-casein glycomacropeptides which have several useful physiological activities.
It is known that .kappa.-casein glycomacropeptides are peptides bonded with sialic acid which are produced by reacting milk .kappa.-casein with rennet or pepsin and are present in cheese whey.
Hitherto, .kappa.-casein glycomacropeptides were produced by a method comprising dissolving .kappa.-casein isolated from cow's milk in deionized water, reacting the obtained solution with pepsin, adding trichloroacetic acid to the solution to precipitate a para-.kappa.-casein fraction, dialyzing the obtained supernatant against deionized water for desalting, and freeze-drying the obtained solution (Bulletin of Experimental Biology and Medicine, 96, 889 (1983)). Another method comprised dissolving the above .kappa.-casein in deionized water, adjusting the pH of the solution to 6.7, reacting the solution with rennet, readjusting the pH to 4.6 to precipitate the para-.kappa.-casein, removing the precipitate, dialyzing the obtained supernatant for desalting, and freeze-drying the obtained solution (Milk Protein, Academic Press Company, pp 200).
However, these methods are conducted in laboratories and are not suitable for mass production.
On the other hand, since the industrial utilization of .kappa.-casein glycomacropeptides has been previously unknown, a method for producing such compounds in large quantities has not been studied.
Since it was reported that after taking .kappa.-casein glycomacropeptides dogs lost their appetite (Bulletin of Experimental Biology and Medicine, 96, 889 (1983)), it has been found that the compounds can be utilized as food materials for the prevention of fat.
Further, since it was found that .kappa.-casein glycomacropeptides were effective to prevent the adhesion of E.coli to cells of the intestines, to protect the infection of influenza (Japanese Unexamined Patent Application No. 63-284133/1988) or to protect the adhesion of tartar to teeth (Japanese Unexamined Patent Application No. 63-233911/1988), the demand for the production of these compounds on a large industrial scale is expected.
Given such conditions, a process for preparing a .kappa.-casein glycomacropeptide from rennet casein curd whey has been reported. (Japanese Unexamined Paten Application No. 63-284199). Since the reaction of the process may proceed without the trichloroacetic acid of the prior art; the obtained compounds can be used as food materials and can be produced in a large quantity. However, the method can not be used with the rennet casein curds which are obtained as a by-product of the rennet casein curd whey.
If the rennet casein curds are not utilized, the production cost of .kappa.-casein glycomacropeptides is expensive.